Although nonsteroidal anti-inflammatory drugs, narcotic analgesics, and antagonistic analgesics are conventionally used as analgesics, there is demand for novel useful analgesics in which the adverse effects of these drugs are reduced.
As compounds having 4-hydroxy-4-phenylpiperidino group and analgesic action, the following compounds are known. For example, compounds represented by Formula (A) are reported in European Journal of Pharmacology, Vol. 43, p253, 1977. ##STR2##
Also compounds represented by Formula (B) are reported in European Journal of Pharmacology, Vol. 72, p305, 1981. ##STR3##
Further compounds (C) are reported in Lzv. Vyssh. Uchebn. Zarved., Khim. Khim. Teknol, Vol. 21, p810, 1978. ##STR4##